A web service is a collection of one or more operations which are published and made available on the Internet. A description of the public interface to the web service is generally provided in a Web Services Description Language (WSDL) document. In order to invoke an operation associated with a web service, input values must be provided in accordance with the web service description document. These values are typically provided as one or more Extended Markup Language (XML) messages, such as Simple Object Access Protocol (SOAP) messages, sent to the web service. The web service then executes the requested operation and returns one or more output values in one or more XML messages.
Companies that want to use one or more of the operations provided by a web service must integrate the web service with the company's business application(s). The integration must be done by software developers making changes to the application(s). This can be a time consuming and expensive process. The costs, in both time and money, increase with each web service integrated with an application. These costs are not insignificant, as an average size business may need to integrate with hundreds of web services. Additionally, if an integrated web service interface changes, the company may incur additional costs to maintain existing integrations or access new functionality provided by the changed web service.